Graphene pn Junction: Electronic Transport and Devices

Low, Tony

doi:10.1007/978-3-642-22984-8_15

Cited by 2 publications

(3 citation statements)

References 114 publications

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“…which is the same result one can obtain by taking the wavefunctions of each region equal to the eigenfunctions of the free electron Dirac Hamiltonian and requiring them to be continuous at the interface 23 . The fact that, even for an abrupt junction, transmission can be lower than one represents the effect of wavefunction mismatch that was mentioned previously.…”

Section: Transmission Modelsupporting

confidence: 53%

“…The reason lies in the simplified way in which transport across the potential steps at the sourcechannel and drain-channel interfaces is treated. In particular, Klein tunneling is included with tunneling probability equal to one, ignoring the quantum-mechanical effect of wavefunction mismatch at the junctions and also the fact that, if the junctions are not perfectly abrupt, electrons incident at non-normal angles need to tunnel through an apparent band gap 23 . The latter effect should be more evident in devices with spacings between the gated part of the channel and the source and drain contacts ("gate underlaps"), where the potential profiles are typically smoother.…”

Section: Introductionmentioning

confidence: 99%

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Semianalytical quantum model for graphene field-effect transistors

Pugnaghi

Grassi

Gnudi

et al. 2014

Journal of Applied Physics

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We develop a semianalytical model for monolayer graphene field-effect transistors in the ballistic limit. Two types of devices are considered: in the first device, the source and drain regions are doped by charge transfer with Schottky contacts, while, in the second device, the source and drain regions are doped electrostatically by a back gate. The model captures two important effects that influence the operation of both devices: (i) the finite density of states in the source and drain regions, which limits the number of states available for transport and can be responsible for negative output differential resistance effects, and (ii) quantum tunneling across the potential steps at the source-channel and drain-channel interfaces. By comparison with a self-consistent non-equilibrium Green's function solver, we show that our model provides very accurate results for both types of devices, in the bias region of quasi-saturation as well as in that of negative differential resistance.Comment: 10 pages, 14 figure

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Section: Transmission Modelsupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Semianalytical quantum model for graphene field-effect transistors

Pugnaghi

Grassi

Gnudi

et al. 2014

Journal of Applied Physics

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“…Graphene as the first two-dimensional material, hosts the relativistic massless Dirac fermions (MDFs) and possesses a lot of exotic physics and possible applications [4]. Especially, the two-dimensional nature of graphene is beneficial to the fabrication of the planar p-n junction (PNJ), which is the basic component of many electronic devices [5,6]. The propagation of MDFs across graphene PNJ has a close analogy to optical negative refraction at the surface of metamaterials but exhibits negative refraction in a more simple and tunable manner [7].…”

Section: Introductionmentioning

confidence: 99%

Anomalous caustics and Veselago focusing in 8-Pmmn borophene p–n junctions with arbitrary junction directions

Zhang

Yang

2019

New J. Phys.

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Negative refraction usually demands complex structure engineering while it is very natural for massless Dirac fermions (MDFs) across the p-n junction (PNJ), this leads to Dirac electron optics. The emergent Dirac materials may exhibit hitherto unidentified phenomenon due to their nontrivial band structures in contrast to the isotropic MDFs in graphene. Here, as a specific example, we explore the negative refraction induced caustics and Veselago focusing of tilted MDFs across 8-Pmmn borophene PNJs. To this aim, we develop a technique to effectively construct the electronic Green's function (GF) in PNJs with arbitrary junction directions. Based on analytical discussions and numerical calculations, we demonstrate the strong dependence of interference pattern on the junction direction. As the junction direction perpendicular to the tilt direction, Veselago focusing or normal caustics (similar to that in graphene) appears resting on the doping configuration of the PNJs, otherwise anomalous caustics (different from that in graphene) occurs which is manipulated by the junction direction and the doping configuration. Finally, the developed GF technique is generally promising to uncover the unique transport of emergent MDFs, and the discovered anomalous caustics makes tilted MDFs potential applications in Dirac electron optics.

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Graphene pn Junction: Electronic Transport and Devices

Cited by 2 publications

References 114 publications

Semianalytical quantum model for graphene field-effect transistors

Semianalytical quantum model for graphene field-effect transistors

Anomalous caustics and Veselago focusing in 8-Pmmn borophene p–n junctions with arbitrary junction directions

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